Last weekend, I noticed that trunk lights (both inside the trunk and on trunk lid) were not as bright as usual. However, when trunk lid was in almost close position, I could see both lights were bright again. As soon as trunk lid moved up to about half open position, both light got dim.

Do these light control by some kind of level switch or else ?

Thanks,

Ching-Ho Cheng

 

I got worse case.
The light inside the trunk was not turned ON when trunk lid was open.
But the light is ON when trunk lid was in almost close position.
Another light on the trunk lid is always ok.
I'm suspecting cable damage or the light module, LMA ecu which need to be initialized.
Any idea from folks?
E60 LCI 528i 2008

 

I wiggled wiring harness coming out of the trunk lid last night. After that, both trunk lights stayed dim all the times despite of trunk lid position. Also, trunk lock did not work either. I could not close trunk. I had to disconnect battery to close trunk. So this is definitely the wiring harness coming out of the trunk lid causing all these problems.

I searched online and saw that others had similar issue with the wiring harness coming out of the trunk lid. I will tackle it tomorrow after work....

 

I unwrapped/cut open the protective cloth on the wires from trunk lid to the main harness (big bunch of wires). 4 wires were in trouble in the area where it joined to main harness. Ground wire (brown color) was broken off, other 3 "thin" wires were in bad shape too, not broken yet. I will repair them tonight with soldering and shrink wrap.

 

The brown wire is the ground wire and the usual culprit. I had problems with the trunk latch which would intermittently work or not, then stopped working completely. I hadn't noticed if the lights etc were working or not, but the brown wire was completely broken off. Spliced the brown wire with 16g wire and taped up the other cracked wires.
Salut, Bob P.

 

I will repair all 4 wires, hopefully this will last for a much longer period than original (12 years).

 

All fixed last night. Ground wire was soldered with an extra silicon wire (longer now) and heat shrink wrapped. Tapped other 4 cracked wires; straight them out first before tapping with electrical tapes. Everything works now as it used to be.

 

My case was the same as others. Several wires were cut or almost cut, so solder all of them.
All problems are gone. Thanks folks.